Hypersensitivity reactions from taxol

Taxol is an antitumor agent in clinical trial that has been shown to have activity against advanced ovarian carcinoma and melanoma. Hypersensitivity reactions (HSRs) have been one of the toxicities observed with administration of this drug. Of 301 patients treated, 32 patients have had definite (27 patients) or possible (five patients) hypersensitivity reactions to taxol. All but one patient had the reaction from the first or second exposure to this agent. Reactions occurred at a variety of doses and were characterized most frequently by dyspnea, hypotension, bronchospasm, urticaria, and erythematous rashes. Thirteen (41%) patients had received premedication designed to prevent such toxicity; nevertheless, they sustained HSRs. Prolonging the drug infusion appears to have somewhat reduced, but not obviated, the risk of HSRs. The cause (taxol itself or its excipient Cremophor EL; Badische Anilin und Soda-Fabrik AG [BASF], Ludwigshafen, Federal Republic of Germany) and the mechanism of these reactions to taxol are unknown. We provide guidelines to prevent or minimize such toxicity and treat reactions if they still occur.

Efficient transfer of genetic material into mammalian cells using Starburst polyamidoamine dendrimers

Starburst polyamidoamine dendrimers are a new class of synthetic polymers with unique structural and physical characteristics. These polymers were investigated for the ability to bind DNA and enhance DNA transfer and expression in a variety of mammalian cell lines. Twenty different types of polyamidoamine dendrimers were synthesized, and the polymer structure was confirmed using well-defined analytical techniques. The efficiency of plasmid DNA transfection using dendrimers was examined using two reporter gene systems: firefly luciferase and bacterial beta-galactosidase. The transfections were performed using various dendrimers, and levels of expression of the reporter protein were determined. Highly efficient transfection of a broad range of eukaryotic cells and cell lines was achieved with minimal cytotoxicity using the DNA/dendrimer complexes. However, the ability to transfect cells was restricted to certain types of dendrimers and in some situations required the presence of additional compounds, such as DEAE-dextran, that appeared to alter the nature of the complex. A few cell lines demonstrated enhanced transfection with the addition of chloroquine, indicating endosomal localization of the complexes. The capability of a dendrimer to transfect cells appeared to depend on the size, shape, and number of primary amino groups on the surface of the polymer. However, the specific dendrimer most efficient in achieving transfection varied between different types of cells. These studies demonstrate that Starburst dendrimers can transfect a wide variety of cell types in vitro and offer an efficient method for producing permanently transfected cell lines.

A global perspective on cadmium pollution and toxicity in non-occupationally exposed population

Cadmium is a non-essential element that has high rates of soil to plant transference compared with other non-essential elements, and certain plant species accumulate large amounts of cadmium from low cadmium content soils. In this paper, levels of cadmium found in major food groups are highlighted together with cadmium levels found in liver and kidney samples from non-occupationally exposed populations. Data on human kidney cadmium levels identified recently, including the study in our own laboratory, are compared with older studies. Human-tissue cadmium contents showed large variations among individuals, but sources of the variation remain unknown. Exposure levels of 30-50 microg per day have been estimated for adults and these levels have been linked to increased risk of bone fracture, cancer, kidney dysfunction and hypertension. Increased mortality was found among individuals showing signs of cadmium renal toxicity compared with those without such signs, suggesting that renal toxicity may be an early warning of complications, sub-clinical or clinical morbidity.

Fructosamine: a new approach to the estimation of serum glycosylprotein. An index of diabetic control

The development of a novel manual method designed to measure serum glycosylprotein as an index of diabetic control is described. The method relies on the ability of ketoamines (fructosamines) to act as reducing agents in alkaline solution. Conditions are described for a simple colorimetric procedure which permits assay of both a synthetic fructosamine and purified albumin while severely limiting the contribution of interfering substances. Applied to whole sera, the measurement is linear with volume of serum assayed. It allows clear discrimination of normal and diabetic populations (p less than 0.001), and is significantly correlated with fasting blood glucose concentration (r = 0.72) and with a thiobarbituric acid procedure for measuring glycosylprotein-derived hydroxymethylfurfural (r = 0.58). The method is rapid (at least 12 samples per hour) and demands only simple equipment.

The hippocampal formation participates in novel picture encoding: evidence from functional magnetic resonance imaging

Considerable evidence exists to support the hypothesis that the hippocampus and related medial temporal lobe structures are crucial for the encoding and storage of information in long-term memory. Few human imaging studies, however, have successfully shown signal intensity changes in these areas during encoding or retrieval. Using functional magnetic resonance imaging (fMRI), we studied normal human subjects while they performed a novel picture encoding task. High-speed echo-planar imaging techniques evaluated fMRI signal changes throughout the brain. During the encoding of novel pictures, statistically significant increases in fMRI signal were observed bilaterally in the posterior hippocampal formation and parahippocampal gyrus and in the lingual and fusiform gyri. To our knowledge, this experiment is the first fMRI study to show robust signal changes in the human hippocampal region. It also provides evidence that the encoding of novel, complex pictures depends upon an interaction between ventral cortical regions, specialized for object vision, and the hippocampal formation and parahippocampal gyrus, specialized for long-term memory.

Functional magnetic resonance imaging of symptom provocation in obsessive-compulsive disorder

BACKGROUND

The new technique of functional magnetic resonance imaging was used to investigate the mediating neuroanatomy of obsessive-compulsive disorder symptoms.

METHODS

Ten patients with obsessive-compulsive disorder and 5 normal subjects were studied via functional magnetic resonance imaging during control and provoked conditions. Data analysis entailed parametric and nonparametric statistical mapping.

RESULTS

Statistical maps (nonparametric; P < 10(-3)) showed activation for 70% or more of patients with obsessive-compulsive disorder in medial orbitofrontal, lateral frontal, anterior temporal, anterior cingulate, and insular cortex, as well as caudate, lenticulate, and amygdala. No normal subjects exhibited activation in any brain region.

CONCLUSIONS

Results of functional magnetic resonance imaging were consistent with past studies of obsessive-compulsive disorder that used other functional neuroimaging modalities. However, paralimbic and limbic activations were more prominent in the present study.

The intravascular contribution to fMRI signal change: Monte Carlo modeling and diffusion-weighted studies in vivo

Understanding the relationship between fMRI signal changes and activated cortex is paramount to successful mapping of neuronal activity. To this end, the relative extravascular and intravascular contribution to fMRI signal change from capillaries (localized), venules (less localized) and macrovessels (remote, draining veins) must be determined. In this work, the authors assessed both the extravascular and intravascular contribution to blood oxygenation level-dependent gradient echo signal change at 1.5 T by using a Monte Carlo model for susceptibility-based contrast in conjunction with a physiological model for neuronal activation-induced changes in oxygenation and vascular volume fraction. The authors compared our Model results with experimental fMRI signal changes with and without velocity sensitization via bipolar gradients to null the intravascular signal. The model and experimental results are in agreement and suggest that the intravascular spins account for the majority of fMRI signal change on T2*-weighted images at 1.5 T.

Mapping by monoclonal antibody detection of glycosaminoglycans in connective tissues

Chondroitin sulphate proteoglycans are widespread connective tissue components and chemical analysis of cartilage and other proteoglycans has demonstrated molecular speciation involving the degree and position of sulphation of the carbohydrate chains. This may, in turn, affect the properties of the glycosaminoglycan (GAG), particularly with respect to self-association and interactions with other extracellular matrix components. Interactions with specific molecules from different connective tissue types, such as the collagens and their associated glycoproteins, could be favoured by particular charge organizations on the GAG molecule endowed by the sulphate groups. So far, it has not been possible to identify and map chondroitins of differing sulphation in tissues, but we have now raised three monoclonal antibodies which specifically recognize unsulphated, 4-sulphated and 6-sulphated chondroitin and dermatan sulphate. These provide novel opportunities to study the in vivo distribution of chondroitin sulphate proteoglycans. We demonstrate that chondroitin sulphates exhibit remarkable connective tissue specificity and furthermore provide evidence that some proteoglycans may predominantly carry only one type of chondroitin sulphate chain.

Regulation of in vitro gene expression using antisense oligonucleotides or antisense expression plasmids transfected using starburst PAMAM dendrimers

Starburst polyamidoamine (PAMAM) dendrimers are a new type of synthetic polymer characterized by a branched spherical shape and a high density surface charge. We have investigated the ability of these dendrimers to function as an effective delivery system for antisense oligonucleotides and 'antisense expression plasmids' for the targeted modulation of gene expression. Dendrimers bind to various forms of nucleic acids on the basis of electrostatic interactions, and the ability of DNA-dendrimer complexes to transfer oligonucleotides and plasmid DNA to mediate antisense inhibition was assessed in an in vitro cell culture system. Cell lines that permanently express luciferase gene were developed using dendrimer mediated transfection. Transfections of antisense oligonucleotides or antisense cDNA plasmids into these cell lines using dendrimers resulted in a specific and dose dependent inhibition of luciferase expression. This inhibition caused approximately 25-50% reduction of baseline luciferase activity. Binding of the phosphodiester oligonucleotides to dendrimers also extended their intracellular survival. While dendrimers were not cytotoxic at the concentrations effective for DNA transfer, some non-specific suppression of luciferase expression was observed. Our results indicate that Starburst dendrimers can be effective carriers for the introduction of regulatory nucleic acids and facilitate the suppression of the specific gene expression.

Long-term improvement of hypercholesterolemia after ex vivo gene therapy in LDLR-deficient rabbits

Familial hypercholesterolemia (FH) is an inherited disorder in humans that is caused by a deficiency of low density lipoprotein receptors (LDLRs). An animal model for FH, the Watanabe Heritable Hyperlipidemic rabbit, was used to develop an approach for liver-directed gene therapy based on transplantation of autologous hepatocytes that were genetically corrected ex vivo with recombinant retroviruses. Animals transplanted with LDLR-transduced autologous hepatocytes demonstrated a 30 to 50 percent decrease in total serum cholesterol that persisted for the duration of the experiment (122 days). Recombinant-derived LDLR RNA was harvested from tissues with no diminution for up to 6.5 months after transplantation.

A novel surfactant nanoemulsion with a unique non-irritant topical antimicrobial activity against bacteria, enveloped viruses and fungi

A novel non-ionic surfactant nanoemulsion designated 8N8 has been tested for its biocidal activity. One percent 8N8 produced effective bactericidal activity against Bacillus cereus, Bacillus subtilis, Haemophilus influenzae, Neisseria gonorrhoeae, Streptococcus pneumoniae, and Vibrio cholerae in 15 minutes. In contrast, most enteric gram-negative bacteria were resistant to 8N8. One percent 8N8 was also virucidal within 15 minutes for all tested enveloped viruses, including Herpes simplex type 1, influenza A and vaccinia viruses. One percent 8N8 also demonstrated fungistatic activity on Candida albicans. The rapid and non-specific inactivation of vegetative bacteria and enveloped viruses, in addition to its fungistatic activity and low toxicity in experimental animals, makes 8N8 a potential candidate for use as a topical biocidal agent.

Inhibition of viral adhesion and infection by sialic-acid-conjugated dendritic polymers

Multiple sialic acid (SA) residues conjugated to a linear polyacrylamide backbone are more effective than monomeric SA at inhibiting influenza-induced agglutination of red blood cells. However, "polymeric inhibitors" based on polyacrylamide backbones are cytotoxic. Dendritic polymers offer a nontoxic alternative to polyacrylamide and may provide a variety of potential synthetic inhibitors of influenza virus adhesion due to the wide range of available polymer structures. We evaluated several dendritic polymeric inhibitors, including spheroidal, linear, linear-dendron copolymers, comb-branched, and dendrigraft polymers, for the ability to inhibit virus hemagglutination (HA) and to block infection of mammalian cells in vitro. Four viruses were tested: influenza A H2N2 (selectively propagated two ways), X-31 influenza A H3N2, and sendai. The most potent of the linear and spheroidal inhibitors were 32-256-fold more effective than monomeric SA at inhibiting HA by the H2N2 influenza virus. Linear-dendron copolymers were 1025-8200-fold more effective against H2N2 influenza, X-31 influenza, and sendai viruses. The most effective were the comb-branched and dendrigraft inhibitors, which showed up to 50000-fold increased activity against these viruses. We were able to demonstrate significant (p < 0.001) dose-dependent reduction of influenza infection in mammalian cells by polymeric inhibitors, the first such demonstration for multivalent SA inhibitors. Effective dendrimer polymers were not cytotoxic to mammalian cells at therapeutic levels. Of additional interest, variation in the inhibitory effect was observed with different viruses, suggesting possible differences due to specific growth conditions of virus. SA-conjugated dendritic polymers may provide a new therapeutic modality for viruses that employ SA as their target receptor.

DNA complexing with polyamidoamine dendrimers: implications for transfection

DNA and polyamidamine (PAMAM) dendrimers form complexes on the basis of the electrostatic interactions between negatively charged phosphate groups of the nucleic acid and protonated (positively charged) amino groups of the polymers. Charge neutralization of both components and subsequent increases of the net positive charge of the complex result in changes in the physicochemistry and biological properties of the complexes. The formation of soluble, low-density and insoluble, high-density complexes was analyzed using UV light absorption and measurements of radioactive labeled DNA. Formation of high molecular weight and high-density complexes depended mainly on the DNA concentration and was enhanced by increasing the dendrimer-DNA charge ratio. Electrostatic charge related effects (attraction or repulsion of charged particles) appeared to be modulated by the generation of dendrimer (size of the polymer). With the progressive increases in the dendrimer-DNA charge ratio (above 20), an increase in the amount of low-density, soluble complexes was observed. Functional analysis revealed that the great majority (>90%) of transfection is carried by low-density, soluble, complexes which only represent approximately 10-20% of total complexed DNA. The ability of the dendrimer to complex and form aggregates with DNA is crucial for efficient transfection and the function of the complexed DNA.

The use of PAMAM dendrimers in the efficient transfer of genetic material into cells

Polyamidoamine (PAMAM) dendrimers have steadily grown in popularity in the past decade in a variety of disciplines, ranging from materials science to biomedicine. This can be attributed in part to their use in applications that range from computer toners to medical diagnostics. PAMAM dendrimers are safe and nonimmunogenic, and can function as highly efficient cationic polymer vectors for delivering genetic material into cells. They have been shown to be as efficient or more efficient than either cationic liposomes or other cationic polymers (e.g. polyethylenimine, polylysine) for in vitro gene transfer. This article will focus on the application of PAMAM dendrimers as a nonviral gene delivery vector from the initial discovery of this capacity to the most recent experimental findings.

Imaging subcortical auditory activity in humans

There is a lack of physiological data pertaining to how listening humans process auditory information. Functional magnetic resonance imaging (fMRI) has provided some data for the auditory cortex in awake humans, but there is still a paucity of comparable data for subcortical auditory areas where the early stages of processing take place, as amply demonstrated by single-unit studies in animals. It is unclear why fMRI has been unsuccessful in imaging auditory brain-stem activity, but one problem may be cardiac-related, pulsatile brain-stem motion. To examine this, a method eliminating such motion (using cardiac gating) was applied to map sound-related activity in the auditory cortices and inferior colliculi in the brain stem. Activation in both the colliculi and cortex became more discernible when gating was used. In contrast with the cortex, the improvement in the colliculi resulted from a reduction in signal variability, rather than from an increase in percent signal change. This reduction is consistent with the hypothesis that motion or pulsatile flow is a major factor in brain-stem imaging. The way now seems clear to studying activity throughout the human auditory pathway in listening humans.

O glycosylation of an Sp1-derived peptide blocks known Sp1 protein interactions

The O-linked N-acetylglucosamine (O-GlcNAc) modification of proteins is dynamic and abundant in the nucleus and cytosol. Several transcription factors, including Sp1, have been shown to contain this modification; however, the functional role of O-GlcNAc in these proteins has not been determined. In this paper we describe the use of the previously characterized glutamine-rich transactivation domain of Sp1 (B-c) as a model to investigate the role of O-GlcNAc in Sp1's transcriptionally relevant protein-to-protein interactions with the TATA-binding-protein-associated factor (TAF110) and holo-Sp1. When the model Sp1 peptide was overexpressed in primate cells, this 97-amino-acid domain of Sp1 was found to contain a dominant O-GlcNAc residue at high stoichiometry, which allowed the mapping and mutagenesis of this glycosylation site. In vitro interaction studies between this segment of Sp1 and Drosophila TAF110 or holo-Sp1 indicate that the O-GlcNAc modification functions to inhibit the largely hydrophobic interactions between these proteins. In HeLa cells, the mutation at the mapped glycosylation site was permissive for transcriptional activation. We propose the hypothesis that the removal of O-GlcNAc from an interaction domain can be a signal for protein association. O-GlcNAc may thereby prevent untimely and ectopic interactions.

Antimicrobial mechanism of action of surfactant lipid preparations in enteric Gram-negative bacilli

Two surfactant lipid preparations (SLPs) were investigated to determine their mechanism of antimicrobial action. 8N8, a water-in-oil emulsion, and W60C, a liposome, both have bactericidal activity against Gram-positive bacteria and non-enteric Gram-negative bacteria. Additionally, W60C is bactericidal for enteric Gram-negative bacilli when suspended in deionized water. Zeta potential measurements suggested that the resistance of Gram-negative bacilli to 8N8 might be caused by ionic repulsion. Addition of 50 micromol 1(-1) ethylene diamine tetra acetic acid in 100 mmol 1(-1) Tris buffer to either SLPs yielded efficient bactericidal activity against Gram-negative bacilli. This appeared to be due to disruption of the outer membrane and the chelation of divalent cations, as the addition of excess calcium inhibited the antimicrobial effect. Electron microscopy studies documented that 8N8 disrupts the bacterial cell wall, lysing the bacteria, while W60C fuses and internalizes within the cell, causing damage without immediate cell lysis. Understanding the mechanisms of action of these biocidal formulations will help to produce improved formulations with broader spectra of activity.

A novel surfactant nanoemulsion with broad-spectrum sporicidal activity against Bacillus species

Two nontoxic, antimicrobial nanoemulsions, BCTP and BCTP 401, have been developed. These emulsions are composed of detergents and oils in 80% water. BCTP diluted up to 1:1000 inactivated>90% of Bacillus anthracis spores in 4 h and was also sporicidal against three other Bacillus species. This sporicidal activity is due to disruption of the spore coat after initiation of germination without complete outgrowth. BCTP 401 diluted 1:1000 had greater activity than BCTP against Bacillus spores and had an onset of action of <30 min. Mixing BCTP or BCTP 401 with Bacillus cereus prior to subcutaneous injection in mice reduced the resulting skin lesion by 99%. Wound irrigation with BCTP 1 h after spore inoculation yielded a 98% reduction in skin lesion size, and mortality was reduced 3-fold. These nanoemulsion formulas are stable, easily dispersed, nonirritant, and nontoxic compared with other available sporicidal agents.

The interaction of plasmid DNA with polyamidoamine dendrimers: mechanism of complex formation and analysis of alterations induced in nuclease sensitivity and transcriptional activity of the complexed DNA

The application of synthetic vectors for gene transfer has potential advantages over virus-based systems. However, little is known about the mechanisms involved in binding of synthetic materials to DNA and the nature of the DNA complexes that result from this interaction. Polyamidoamine (PAMAM) dendrimers are unique polymers with defined spherical structure. Dendrimers bind DNA to form complexes that efficiently transfect cells in vitro. We examined the formation of DNA/dendrimer complexes and found it based entirely on charge interaction. Electronmicroscopic examination of the complexes indicated that the majority of the plasmid DNA is contracted into isolated toroids, but also revealed larger, irregular aggregates of polymer and DNA. The binding of plasmid DNA to dendrimer appears to alter the secondary and tertiary structure, but does not fragment the DNA or alter its primary structure. Complexed DNA is protected against degradation by either specific nucleases or cellular extracts containing nuclease activity. While the initiation of transcription in vitro from promoters (for either T7 polymerase or eukaryotic RNA polymerase II) in dendrimer-complexed DNA is inhibited, elongation of the RNA transcript and translation do not appear to be affected. These resemble alterations of the DNA function when complexed with naturally-occurring polycations like non-acetylated histones. However, DNA complexed to dendrimer appears to maintain transcriptional activity while histone complexes at similar charge ratios do not. These results elucidate some aspects of the interaction between PAMAM dendritic polymers and DNA, and could lead to improvements in the design of polymers or formation of DNA complexes that will increase the efficiency of non-viral gene transfer.

Histological survey of tumours of the horse, with particular reference to those ofthe skin

In a histological survey of 244 tumerous growths from 155 horses, the tumours commonly found were fibromas, squamous cell carcinomas, sarcoids and papillomas, most frequently affecting the skin, external genitalia, eye and orbit. The histological features that differentiate fibroblastic citaneous growths are detailed so that the clinical behaviour of these distinct neoplasms can be studied.

Clinical usefulness of estimation of serum fructosamine concentration as a screening test for diabetes mellitus

Fructosamine, a putative measure of serum glycosylated proteins, was measured in 74 subjects referred for oral glucose tolerance tests. A normal range (mean (2 SD] of 1.6 (0.4) mmol/l (40(10) mg/100 ml) derive from results obtained in 83 healthy non-diabetic volunteers permitted the detection of 15 out of 17 (88%) subjects with proved diabetes and yielded only five (9%) false positive diagnoses. Fructosamine concentrations correlated significantly (p less than 0.001) with fasting plasma glucose concentrations (r = 0.76) and glycosylated haemoglobin concentrations (r = 0.70). A longitudinal study suggested that fructosamine concentration was an index of intermediate term (one to three weeks) blood glucose control. Fructosamine concentration was not related to uraemia and did not depend on albumin or total protein concentrations, provided that serum albumin concentrations remained above 30 g/l. Estimation of fructosamine concentrations is a fully automated procedure and may provide a simple means of screening for diabetes mellitus.

Application of membrane-based dendrimer/DNA complexes for solid phase transfection in vitro and in vivo

In this study a general description of the use of solid support membranes as the device for DNA delivery mediated by PAMAM dendrimers is presented. In contrast to the other DNA carriers, dendrimer/DNA complexes retain the ability to transfect after drying, which enabled coating or incorporation of complexes into poly(DL-lactide-co-glycolide) or collagen-based bioerodable membranes. These studies provide support for the use of this technology for in vitro and in vivo transfection of skin cells. Expression of luciferase or green fluorescent protein from pCF1-Luc and pEGFP1 plasmids indicated that dendrimer/DNA complexes can mediate transfection after dissociation from the solid support and/or when retained on the surface of the membranes. Modification of the membranes by incorporation of an anionic lipid, phosphatidyl glycerol (PG) at 1-5% concentrations, resulted in more efficient in situ transfection, particularly with dendrimer/DNA complexes formed at the low charge ratios (1-5). We also report data supporting the feasibility of membrane-based dendrimer/DNA complexes, particularly formed at lower than neutralizing conditions, for topical in vivo delivery of DNA to hairless mouse skin.

Influence of vitamin D receptor genotype on bone mineral density in postmenopausal women: a twin study in Britain

OBJECTIVES

To investigate the possible association between vitamin D receptor genotype and bone mineral density in a large group of postmenopausal twins.

DESIGN

Cross sectional twin study.

SETTING

Twin population based in Britain.

SUBJECTS

95 dizygotic (non-identical) pairs of twins and 87 monozygotic (identical) pairs of twins aged 50-69 years, postmenopausal, and free of diseases affecting bone, recruited from a national register of twins and with a media campaign.

MAIN OUTCOME MEASURES

Bone mineral density measured at the hip, lumbar spine, forearm, and for the whole body by dual energy x ray absorptiometry in relation to differences in the vitamin D receptor genotype.

RESULTS

At all sites the values of bone density among dizygotic twins were more similar in those of the same vitamin D receptor genotype than in those of differing genotype, and the values in the former were closer to the correlations seen in monozygotic twins. Women with the genotype that made them at risk of osteoporotic fracture had an adjusted bone mineral density that was significantly lower by SD 0.5 to 0.6 at the hip, lumbar spine, and for the whole body. The results could not be explained by differences in age, weight, years since menopause, or use of hormone replacement therapy.

CONCLUSIONS

The findings that in postmenopausal women in Britain bone density-particularly at the hip and spine-is genetically linked and specifically associated with the vitamin D receptor genotypes should lead to novel approaches to the prevention and treatment of osteoporosis.